1. Field of the Invention
This invention relates to the lighting arts and, more particularly, to a direct-indirect lighting fluorescent luminaire comprising a field-reversible reflector that may be installed to achieve efficient and uniform illumination of a floor and ceiling area, or of just a floor area as necessitated by a specific installation.
2. Description of the Related Art
Fluorescent lighting technology has greatly advanced since its inception in the late 1930s responsive to market requirements for energy efficient lighting systems. Lamp and ballast manufacturers have developed fluorescent lamp-ballast systems with vastly improved energy efficiency that are convenient to use and install. As one example, ANSI T-5 lamps are a type of fluorescent lamp currently used which operate very efficiently at temperatures above ambient room temperature.
Direct-indirect lighting systems are known in the art. Suspended indirect lighting systems are those in which a luminaire containing a lamp or lamps directs light onto a ceiling surface whereby it is reflected downwardly to the area below or simply used to illuminate the area above. These luminaires normally provide a direct or “down” lighting component as well as an indirect or “up” lighting component through the top of the luminaire housing which is either open, has slots disposed in a portion of the luminaire, or includes a light transmitting element such as a lens cover.
Many up light and down light luminaires are designed to produce varying up and down light patterns, depending primarily on the design of a reflector or reflectors disposed proximate the lamps in the luminaire housing. However, this arrangement often requires a purchaser or lighting designer to know exactly what type of lighting is necessary for a given location when ordering or purchasing the fixtures. In many applications, up light is not necessarily required or desirable and as such, a fixture that is configured for up lighting can not be used in a strictly down lighting application.
Fluorescent luminaires utilizing up and down light reflectors have enjoyed widespread acceptance because of their efficiency in converting electrical energy to light energy, their favorable spectral emissions, and their ability to direct light in several directions. However, there have remained problems in their use and manufacture. One disadvantage with existing direct-indirect lighting luminaires is that in many designs, the luminaires are not capable of providing both direct and indirect lighting, or only direct lighting as required by the installation application.
Another disadvantage in the prior art is that luminaires capable of selectively providing both direct-indirect lighting and direct only lighting have complex structures that are not well adapted for field configuration and installation. A proliferation of plates, clips, screws, bolts, nuts and other fasteners is typically required when attempting to convert a direct-indirect type luminaire to a direct only luminaire in the field. These small parts are easily lost, dropped and misplaced and are often difficult to find thereafter.
Additionally, the field installer of these prior art devices requires a great deal of additional labor time, and thus money, to convert from one type of luminaire to another. Furthermore, the complexity of the parts necessary to provide conversion kits for these prior art luminaires makes them more costly than a luminaire that is ordered for a specific application. Accordingly, it is desirable to have a luminaire that is capable of being converted from a direct-indirect lighting type of fixture to a direct only type of fixture with minimal effort and with very few additional parts.